US 11,722,979 B2
Method for precise timestamping of narrowband signals in the presence of multipath
Mainak Chowdhury, Redwood City, CA (US); and Philip Kratz, Redwood City, CA (US)
Assigned to ZaiNar, Inc., Redwood City, CA (US)
Filed by ZaiNar, Inc., Redwood City, CA (US)
Filed on Apr. 10, 2020, as Appl. No. 16/846,030.
Claims priority of provisional application 62/832,096, filed on Apr. 10, 2019.
Prior Publication US 2020/0329449 A1, Oct. 15, 2020
Int. Cl. G01S 5/02 (2010.01); H04L 7/00 (2006.01); H04L 7/06 (2006.01); H04W 56/00 (2009.01); H04W 72/0446 (2023.01)
CPC H04W 56/0065 (2013.01) [G01S 5/02 (2013.01); H04L 7/007 (2013.01); H04L 7/06 (2013.01); H04W 56/001 (2013.01); H04W 72/0446 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for detecting times-of-arrival of signals comprising, at a receiving node:
during a first time slot, receiving a first signal comprising a first carrier signal:
characterized by a first carrier frequency; and
modulated by a first template signal defining a first code sequence characterized by a transmitter chip period;
demodulating the first signal according to a first local oscillator frequency to generate a first received baseband signal, the first local oscillator frequency and the first carrier frequency defining a first desynchronization ratio in irreducible form characterized by a first denominator greater than a threshold denominator;
sampling the first received baseband signal at the transmitter chip period to generate a first set of digital samples;
generating, on a fine time grid, a first reconstructed baseband signal based on the first set of digital samples, the fine time grid characterized by a time resolution less than the transmitter chip period;
calculating, on the fine time grid, a first cross-correlation function comprising a cross-correlation of the first reconstructed baseband signal and the first template signal; and
calculating, on the fine time grid, a first time-of-arrival of the first signal based on a first earliest peak time in a first set of peak times, each peak time in the first set of peak times corresponding to a local maximum in a first amplitude response of the first cross-correlation function.